Former President Bill Clinton on Tuesday endorsed an effort to make Illinois the 13th state to legalize gay marriage.

“Our nation's permanent mission is to form a 'more perfect union' – deepening the meaning of freedom, broadening the reach of opportunity, strengthening the bonds of community,” Clinton said in a statement released by Illinois Unites for Marriage. “That mission has inspired and empowered us to extend rights to people previously denied them. Every time we have done that, it has strengthened our nation. Now we should do it again, in Illinois, with marriage equality.”

“Since the days of Abraham Lincoln, Illinois has stood for the proposition that all citizens should be treated equally under the law. Lincoln himself came to Springfield in search of opportunity, and he dedicated his life to securing equal opportunity for all citizens. I believe that for Illinois and for our nation as a whole, in the 21st century that must include marriage equality.”

Clinton is the second president to endorse the effort in Illinois. Last year, President Barack Obama lent his support.

(Related: Gay marriage supporters in Illinois say they have the votes.)